Groundwater Storage Research Articles

Global land subsidence mapping reveals widespread loss of aquifer storage capacity

Groundwater overdraft gives rise to multiple adverse impacts including land subsidence and permanent groundwater storage loss. Existing methods are unable to characterize groundwater storage loss at the global scale with sufficient resolution to be relevant for local studies. Here we explore the interrelation between groundwater stress, aquifer depletion, and land subsidence using remote sensing and model-based datasets with a machine learning approach. The developed model predicts global land subsidence magnitude at high spatial resolution (~2 km), provides a first-order estimate of aquifer storage loss due to consolidation of ~17 km3/year globally, and quantifies key drivers of subsidence. Roughly 73% of the mapped subsidence occurs over cropland and urban areas, highlighting the need for sustainable groundwater management practices over these areas. The results of this study aid in assessing the spatial extents of subsidence in known subsiding areas, and in locating unknown groundwater stressed regions.

Small Surface Water and Groundwater Storage Projects (DOI)

Small Surface Water and Groundwater Storage Projects (DOI)

Storage in the deep aquifer: Stochastic process in time and frequency domain using groundwater level response to seismic activation of the Tohoku earthquake, Japan, 2011

AbstractThis study delves into the interplay of Rayleigh wave‐groundwater‐aquifer dynamics, utilizing seismic data from designated stations, particularly the magnitude 9 event on March 11, 2011 (02:46:23 PM epicenter), Tohoku earthquake, Japan. Auto spectra uncover significant peaks, linking groundwater level with the vertical motion of Rayleigh waves. High coherence between groundwater levels and seismogram vertical displacements confirms this connection. Coherence analysis validates it at the significant frequency bands. Groundwater storage coefficient estimation aligns with typical values of confined aquifers, ranging from 1.0E‐05 to 1.0E‐03. This consistency applies across different methods and other earthquake events, highlighting seismic impact. The findings enhance understanding of aquifer behavior during seismic events, aiding groundwater management and earthquake readiness in susceptible regions. Further research should expand datasets for coefficient accuracy. Insights advance aquifer behavior comprehension during seismic events, guiding groundwater management and earthquake readiness in prone areas.

Continuing Severe Water Shortage in the Water‐Receiving Area of the South‐To‐North Water Diversion Eastern Route Project From 2002 to 2020

AbstractThe water‐receiving area of the South‐to‐North Water Diversion Eastern Route Project (SNWDP‐ER) is one of the most severely affected water‐shortage areas in China, and no previous study has been conducted on the changes in water storage in this area. In this study, we combined the latest Gravity Recovery and Climate Experiment (GRACE) And GRACE Follow‐On products with global models for the first time to analyze changes in water storages in this area from 2002 to 2020, and to investigate the effects of climate change and human activity on changes in water storage. We found that SNWDP‐ER aided the recovery of surface water (nongroundwater) with a recovery rate of 9.44 ± 1.65 mm/yr after its implementation, but had little effect on the recovery of groundwater and terrestrial water storage in the water‐receiving area. Before the SNWDP‐ER was implemented, the rates of decrease of groundwater and terrestrial water storage were only −1.59 ± 0.58 and −5.18 ± 0.75 mm/yr, respectively. After implementation, the rates of decrease of groundwater and terrestrial water storage were −17.7 ± 1.27 and −8.16 ± 1.18 mm/yr, respectively. Groundwater decline, accelerated by human activity and climate change, has led to an accelerated decline in terrestrial water storage. Effects of SNWDP‐ER and stringent policies reducing groundwater use, along with largely increased precipitation in North China on groundwater storage after year 2020 need to be examined in the future. Our results have important implications for the management and evaluation of SNWDP‐ER.

Streamflow Composition and Water “Imbalance” in the Northern Himalayas

AbstractThe Yarlung Zangbo River (YZR) is the largest river in the northern Himalayas, providing crucial water resources for downstream. A full understanding of the streamflow dynamics and regional water budget is critical to secure water security of the Himalayan water tower. Here we establish a comprehensive hydrological model to simulate the precipitation‐runoff‐evapotranspiration‐groundwater‐streamflow complex in the YZR basin. We decipher contributions of different water sources (e.g., precipitation, meltwater, groundwater) to YZR's streamflow and estimate that groundwater sustains ∼36% of annual streamflow in the YZR, while precipitation and melt surface runoff contribute 40% and 24%, respectively. Combining modeling, observation and reanalysis data, our results reveal a water “imbalance” that ∼31% of annual precipitation and meltwater (∼333 mm yr−1 or ∼85 km3 yr−1) is unaccounted for in the YZR basin. We propose that the “excess water” discharges to deep fractured bedrock aquifers, which is promoted by widespread permeable active structures (e.g., faults, fractures). This hypothesis is supported by groundwater storage (GWS) estimates where inclusion of the deep groundwater bridges the discrepancy between baseflow‐derived (shallow) GWS and those derived from the Gravity Recovery and Climate Experiment satellite data. The deep groundwater most likely flows across basins, bypasses streams, and finally discharges to downstream aquifers in the Indo‐Gangetic Plain as mountain block recharge. This study not only provides a comprehensive analysis of the streamflow composition in the YZR, but also contributes to shaping a more complete picture of the functionality of the Himalayan water tower, highlighting the importance of groundwater in regional water transfers.

Comparative Effect of Varied Dietary Plant Protein Sources on Growth Performance of Rohu (<i>Labeo rohita Hamilton</i>)

Rohu fingerlings (average weight 5.24 ± 0.46 g) were reared for 8 weeks on four totally plant protein based test diets of which control diet (T-I) consisted of soybean meal, groundnut cake and rice bran. In other three diets, mustard cake (roasted) was incorporated at 3 different proportions replacing soybean meal and groundnut oil cake. The fishes were maintained in triplicate treatment groups having 10 fishes in each in a flow-through system fitted with fiber glass tanks (60 I capacity) with a flow rate of 1.5 1/h. Stored ground water was used for fish rearing. The diets were isonitrogenous and isoenergetic. The growth performance was significantly higher (P < 0.01) in T-I; there was no difference in growth between T-2 and T-3 groups, and growth performance was significantly lower in T-4 groups. The feed cost (Rs/kg) were 9.15, 8.50, 8.10 and 7.90, respectively for T-1, T-2, T-3 and T-4. It may be concluded that roasted mustard cake can be incorporated up to 35 per cent (w /w) in carp diet.

A shrinkage-free approach for fusing GRACE-based total water storage changes with models using wavelet multiresolution analysis

The observations from Gravity Recovery and Climate Experiment (GRACE) satellites provide total water storage changes (TWSC) at ∼300 km or larger spatial scales. To obtain information at a higher spatial resolution, suitable for management purposes, previous studies combined GRACE TWSC maps with information from hydrological models via assimilation techniques (e.g. CLSM-DA), or with external observations via scaling and machine learning approaches. Both techniques may introduce shrinkage errors, a reduction in amplitude of long spatial wavelength signals, and distorting water budgets at basin scale best observed by GRACE. Here, we present a fusion approach based on wavelet multiresolution analysis to combine long-wavelength GRACE TWSC observations with short-wavelength measurements of TWSC from the GLDAS Noah model in the contiguous United States (CONUS). We decompose TWSC maps into building blocks at different spatial wavelengths, examine their statistical characteristics, and combine complementary components at wavelet coefficient levels. The fused TWSC is then obtained by inverse wavelet transform. A spectral analysis indicates that the fused TWSC comprises frequency content that balances spectral characteristics of both input datasets. The fused TWSC dataset possesses enhanced details in the spatial domain, while it accurately quantifies the water budget and its long-term spatial trend at basin scale during 2003–2015, showing a good agreement with GRACE estimates. Independent validation against elastic hydrologic loading deformation measured at ∼2000 GNSS stations across CONUS shows similar overall performance for GRACE and fused datasets, while it outperforms GRACE in modeling groundwater storage changes in CONUS when compared to CLSM-DA.

Interannual hydrological variability in the Mississippi River Basin based on contemporary geodetic measurements and land surface models

The impact of climate change on terrestrial water storage (TWS) is critical for understanding the global hydrological process. The Global Positioning System (GPS) measurements, Gravity Recovery and Climate Experiment (GRACE), and GRACE Follow-On (GFO) data were used to measure the processes involved in the hydrological process in the Mississippi River Basin (MRB) from 2002 to 2021. The common-mode component (CMC) of the GPS network in the MRB obtained using principal component analysis (PCA) was utilized to study the hydrological loading deformation. The data from GRACE/GFO and hydrological models revealed a long-term trend of reduction in the TWS and obvious depletion of the groundwater storage (GWS) in the southwestern part of the MRB. Both GRACE/GFO and the GPS can accurately detect elastic land deformations in the MRB due to hydrological anomalies caused by El Niño/ Southern Oscillation (ENSO), while the sensitivity of GPS in Tennessee regions to net precipitation around 2016 is higher than that of GRACE/GFO. Furthermore, numerous interannual fluctuations and long-term periodic signals observed in both GPS and GRACE/GFO measurements are found to be intimately connected with hydrological processes and ENSO. The findings demonstrate that modern geodetic methods are useful in monitoring the impacts of climate change on hydrological process.

Integrating shallow head measurements and InSAR data to quantify groundwater-storage change in San Joaquin Valley, California (USA)

Monitoring groundwater storage is essential for sustainable groundwater management. Storage can be quantified by considering the two main components through which storage change is expressed: saturation changes and deformation of aquifer materials. Here, these components were quantified using a selected area in California’s San Joaquin Valley (USA). First, this involved following existing observational approaches: quantifying the component expressed through saturation changes by identifying head measurements from shallow wells and scaling by specific yield. In the San Joaquin Valley, existing approaches to estimate the deformation component are to ignore it or approximate it with a simple linear relation to measured head. However, head and deformation measurements made at extensometers revealed that assuming a linear relationship between deformation and head might provide a poor estimate, particularly during periods in which measured head is rising. Instead, InSAR-derived surface deformation measurements were used to quantify the deformation component of storage changes. This showed that the two components—saturation and deformation—accounted for storage declines of equal magnitude over 2015–2021, suggesting that the deformation component should not be neglected when estimating storage changes in regions with subsidence. Summing the two calculated components gave a new estimate of the total storage change that captured the major trends seen in independent estimates, while better accounting for the deformation component. An additional benefit is that this method accounts for the deformation component in the unconfined aquifer. This method to quantify total storage change can be a practical and effective tool to support groundwater management.

Characterization of subsurface pathways contributing to freshwater salinization of urban streams using electrical and electromagnetic imaging techniques

Salinization of inland fresh surface waters in temperate climates is a growing concern due to increasing salt inputs from sources including chloride (Cl)-containing road salt de-icers, industrial waste, and landfill leachate. Groundwater pathways play an important role in the year-round delivery of Cl to streams, but quantifying this pathway, including spatiotemporal variability and amount of Cl mass stored in the subsurface, is challenging. The objective of this study was to demonstrate, evaluate, and compare the potential applications of the geoelectrical techniques – electromagnetics (EM) and direct current (DC) resistivity – for mapping salt contamination in shallow urban groundwater and characterizing the groundwater pathways delivering Cl to urban streams. EM and DC surveys were conducted (3D mapping and 2D time-lapse) across a 20 m salt-impacted stream section and surrounding riparian zone that is located near an arterial road and parking lot. Groundwater samples and soil cores were also collected to validate the geoelectrical results. Both the EM and DC surveys detected high salt concentrations in the shallow subsurface (up to 3 m depth) near the road, parking lot, and stream; however, DC more accurately represented groundwater Cl concentrations. DC results were used to calculate the total Cl mass in the subsurface, with the spatial mass distribution used to infer the temporal variability in the subsurface salt plume. Finally, time-lapse DC showed that the highest groundwater salt concentrations existed near the stream between June and October – this is expected to contribute to the elevated salt concentrations in the stream during summer months. This study has shown that EM and DC can be useful for identifying groundwater salt concentration, storage, and transport in a non-intrusive and efficient manner, making them valuable field tools for characterizing and quantifying groundwater salt pathways to urban streams.

The influence of the 2022 extreme drought on groundwater hydrodynamics in the floodplain wetland of Poyang Lake using a modeling assessment

The 2022 extreme drought in Poyang Lake (China) caused severe damage to a wide range of sectors. It also emphasized the fact that, even in regions with abundant surface water resources, groundwater resource is still a crucial component of drought management strategies. However, providing up-to-date assessments of groundwater response remains challenging due to the limited data in complex floodplain settings. This study uses a groundwater flow modeling FEFLOW to investigate the influences of the most extreme drought in 2022 on groundwater hydrology in the floodplain wetland of Poyang Lake. Model simulation indicates that the extreme drought led to a significant decrease in floodplain groundwater levels, with a maximum drop of about 5 m. In addition, the extent of the groundwater level drop varies significantly across the floodplain wetland, particularly for the strongest impact (drop > 4 m) occurring in the eastern area of the floodplain. It is expected that the extreme drought accelerates the groundwater discharge rate that is about 3 times than that of the normal year, and thus resulting in a losing condition of the floodplain wetland. On an annual scale, the groundwater discharge of the floodplain wetland in 2022 is estimated to be about 14.5 times than that of a normal year, demonstrating a significant attenuation of groundwater storage under drought environments. The reduction in rainfall combined with the associated low lake level is most likely to exert substantial influences on reduced floodplain groundwater storage. This study is the first attempt to interrogate the response of wetland groundwater to the unpredictable drought event in Poyang Lake, contributing to improved understanding of future water resources allocation and drought resistance strategy.

Mechanism the land subsidence from multiple spatial scales and hydrogeological conditions – A case study in Beijing-Tianjin-Hebei, China.

Study regionBeijing-Tianjin-Hebei (BTH) region, China Study focusBTH has long been suffering from severe and uneven land subsidence. Finding out the spatial evolution of land subsidence is helpful to collaborative prevention and control. We innovatively revealed the spatial distribution of land subsidence from the mountains to the coastal area along four hydrogeological profiles, and inferred the land subsidence mechanism on the overall scale, local plain scale and typical regional scale. Small Baseline Subsets Interferometric Synthetic Aperture Radar was employed to collect displacement information in the BTH region from January 2012 to January 2020. We obtained groundwater storage data from the Gravity Recovery and Climate Experiment. New hydrological insights for the regionOn the overall scale, from 2012 to 2019, the Changping-TongZhou district of Beijing suffered the most serious land subsidence, with an annual subsidence rate of 159 mm and a cumulative subsidence as high as 928 mm. On the local plain scale, areas experiencing severe subsidence were generally located in the central plain. Fractures in the area obviously influenced the spatial distribution of subsidence. On the typical regional scale, a positive correlation was found between land subsidence and groundwater depletion. The relationship between precipitation and land subsidence in Hebei was the most convincing (R2 = 0.64). This study provides a scientific basis for regional coordination in land subsidence control. Data availabilityData can be provided by the corresponding authors upon request.

Assessing Terrestrial Water Storage Variations in Southern Spain Using Rainfall Estimates and GRACE Data

This paper investigates the relationship between rainfall, groundwater and Gravity Recovery and Climate Experiment (GRACE) data to generate regional-scale estimates of terrestrial water storage variations in the Andalucía region of southern Spain. These estimates can provide information on groundwater depletion (caused by periods of low rainfall or droughts) and groundwater recovery. The spatial distribution of groundwater bodies in southern Spain is complex and current in situ groundwater monitoring methods are deficient, particularly in terms of obtaining representative samples and in implementing and maintaining groundwater monitoring networks. The alternative approach proposed here is to investigate the relationship between precipitation time series and changes in the terrestrial water storage estimated from GRACE observations. The results were validated against the estimated fluctuation in regional groundwater. The maximum correlation between the mean groundwater level and the GRACE observations is 0.69 and this occurs at a lag of one month because the variation in gravity is immediate, but rainfall water requires around one month to travel across the vadose zone before it reaches the groundwater table. Using graphical methods of accumulated deviations from the mean, we show that, in general, groundwater storage follows the smooth, multi-year trends of terrestrial water storage but with less short-term trends; the same is true of rainfall, for which the local trends are more pronounced. There is hysteresis-like behaviour in the variations in terrestrial water storage and in the variations of groundwater. In practical terms, this study shows that, despite the abnormal dryness of the Iberian Peninsula during the 2004–2010 drought, the depleted groundwater storage in Andalucía recovered almost to its pre-drought level by 2016. In addition, groundwater storage and terrestrial water storage show very similar trends but with a delay in the groundwater trend.

Widespread aquifer depressurization after a century of intensive groundwater use in USA.

Water supplies for household use and irrigated agriculture rely on groundwater wells. When wells are drilled into a highly pressurized aquifer, groundwater may flow up the well and onto the land surface without pumping. These flowing artesian wells were common in the early 1900s in the United States before intensive groundwater withdrawals began, but their present-day prevalence remains unknown. Here, we compile and analyze ten thousand well water observations made more than a century ago. We show that flowing artesian conditions characterized ~61% of wells tapping confined aquifers before 1910, but only ~4% of wells tapping confined aquifers today. This pervasive loss of flowing artesian conditions evidences a widespread depressurization of confined aquifers after a century of intensive groundwater use in the United States. We conclude that this depressurization of confined aquifers has profoundly changed groundwater storage and flow, increasing the vulnerability of deep aquifers to pollutants and contributing to land subsidence.

Dam periodic storage drives the spatial pattern of vegetation towards banded evolution

Emerging and fragile ecosystems such as reservoir riparian zones are of increasing concern with the increasing number of damming projects worldwide. Current knowledge of riparian vegetation in reservoirs focuses on the individual and community level, with little understanding of spatial patterns and ecological processes at the landscape level. Here, we demonstrate the evolution process, evolution direction, and evolution mechanism of vegetation spatial patterns under persistent and periodic inundation disturbances in the reservoir riparian zone, through coupled analyses of landscape evolution and ecological processes, using continuous years of drone observation data in the riparian zones of two major reservoirs, Xiaowan and Nuozhadu of the Lancang River. We found that vegetation landscape evolution is driven by seed dispersal, environmental factors fluctuations, species tolerance differences, and competition for resource availability, showing a clear trend towards banded evolution. Ecological niche processes such as periodic wet-dry environmental filtering and interspecific competition dominated the formation of vegetation banding patches, and neutral processes of random seed dispersal dominated the areas where banding patches were formed. The water requirements of plants during the exposing period lead to a greater influence of environmental factors that are closely related to water, such as net rainfall, sunshine hours, groundwater storage, and soil moisture. Water redistribution between vegetated and bare ground patches is key to their formation and stability in the upper part of the riparian zone, where drought stress is severe, while in the lower part, vegetation is mainly affected by inundation stress during flooding periods. Therefore, riparian vegetation restoration is critical to maintain a certain area of bare ground patches for drought areas in the exposing period, in contrast to the emphasis on vegetation patch coverage. And it is possible to carry out spatial planning based on the development trend of the belt distribution, taking into account the flood and drought tolerance of the species as well as the fluctuating rhythms of the main factors, such as the rainfall, which is worth exploring further.

Examining the change in groundwater flow patterns: A case study from the plain area of the Baiyangdian Lake Watershed, North China

Examining the evolution of groundwater flow patterns is critical to understanding the hydrological cycle and plays an important role in the sustainable management of water resources and ecosystems. In this study, the plain area of the Baiyangdian Lake Watershed (PBW) was chosen as a typical area for severe water scarcity and ecological crisis in the North China Plain. We investigated the temporal and spatial variability in groundwater flow patterns from a holistic view of the water cycle in the PBW and explored more sustainable water resources management using multiple methods, including field surveys, historical data review, statistical analysis, and numerical groundwater modelling. The results show that the groundwater storage decreased by 494 × 108 m3 across the PBW from 1965 to 2019, while the groundwater level presented a decreasing trend for most of the period, which resulted in changes of Baiyangdian Lake and groundwater interactions. Human factors, such as groundwater extraction and water transfer projects, significantly influenced the evolution of groundwater flow patterns by generating a greater contribution of human factors to groundwater balance (54.23%) than that of climate change (45.77%). The hydrodynamic simulations imply that the interaction between groundwater and Baiyangdian Lake was dominated by groundwater recharging the river under natural conditions, and the influence depth of the interaction zone was within about 80 m underground; however, under anthropogenic disturbance, their interaction was altered to the lake recharging groundwater, with a maximum influence depth up to 135 m. Furthermore, considering the systematicity and zoning of the water cycle, we proposed a combination of different strategies, including restricted groundwater exploitation, increased water diversion and water use efficiency, and managed aquifer recharge, which could restore groundwater levels and groundwater storage over a 20-year period to realize sustainable groundwater development. This study highlights the spatiotemporal groundwater flow patterns in a changing environment and the associated hydrogeological processes and provides insights towards the development of more effective water management strategies.

Coupling Simulation and Prediction of Sustainable Utilization of Water Resources in an Arid Inland River Basin under Climate Change

The arid endorheic basin of northwest China is characterized by rich land resources, water shortage, and a fragile ecological environment. The establishment of a credible coupling model of groundwater and surface water based on multi-source observation data is an effective means to study the change in basin water cycles and the sustainable utilization of water resources in the past and future. Based on the latest understanding of hydrogeological conditions, hydrology and water resource utilization data in the middle reaches of the Heihe River Basin (HRB), this paper constructs an up-to-date coupling model of surface water and groundwater to study the water balance change of the basin. The water resources data series under historical replay and CMIP5 climate model prediction are constructed to predict future changes in water resources. The study shows that, under the joint influence of natural conditions and human activities, the average annual recharge of groundwater in the study area from 1990 to 2020 is 17.98 × 108 m3/a, the average annual discharge is 18.62 × 108 m3/a, and the difference between recharge and discharge is −0.64 × 108 m3/a. The total groundwater storage is −19.99 × 108 m3, of which the groundwater storage from 1990 to 2001 was −17.52 × 108 m3 and from 2002 to 2020 was −2.47 × 108 m3. Abundant water from 2002 to 2020 in the basin significantly improved the loss of groundwater storage. Under the prediction of historical reappearance and the CMIP5 CNRM-CM5 model RCP4.5 and RCP8.5 pathways, the groundwater level of the Heihe River–Liyuanhe River inclined plain falls first because the HRB has just experienced a wet season and then rises according to future climate change. The groundwater level of the inclined plain east of the Heihe River and Yanchi basin decreases continuously because of the change in water cycle caused by human activities. The erosion accumulation plain is located in the groundwater discharge zone, and the water level is basically stable. Under the conditions of water resource development and utilization, the runoff of Zhengyixia hydrological station cannot meet the requirements of the “97 Water Dividing Plan” of the State Council in most years in the future, and the ecological and production water in the lower reaches of HRB cannot be effectively guaranteed. With the implementation of water-saving irrigation under the RCP4.5 and RCP8.5 scenarios, the runoff of Zhengyixia can meet the “97 Water Diversion Plan”. It is suggested to further improve the level of agricultural water savings in the middle reaches of the HRB and control the reasonable scale of cultivated land in order to reduce water consumption in the middle reaches of the HRB and implement sustainable utilization of water resources in the HRB.

Depth‐based correlation analysis between the density of lineaments in the crystalline basement's weathered zones and groundwater occurrences within the Voltaian basin, Ghana

AbstractGeological structures have been shown by studies to have influence on the occurrence, storage and transportation of groundwater. Understanding the structural network of an area unearths a deep insight into the groundwater dynamics of the area. A geological structural analysis was carried out to reveal the geological structural network of Ghana's Voltaian basin. Using aeromagnetic data, structural density models were generated using the Center for Exploration Targeting grid analysis technique for two depth ranges (that is up to 100 m and 300 m) over the Voltaian basin. The total length of geological structures (lineaments) delineated at depths up to 100 m and 300 m were more than 5000 km and more than 8000 km, respectively. Given this, the study area was observed to be structurally dense at each of the aforementioned depths. The structural density models were discretized into five classes (very low, low, moderate, moderately high and very high regions), each of which was evaluated to determine their spatial association with known locations of groundwater occurrences within the study area using the frequency ratio technique. Frequency ratio results for both structural density models derived at 100 m and 300 m depths show the existence of a strong correlation between high structural density model classes and the known groundwater occurrences. The structural density models were further evaluated using the receiver operating characteristics curve. The area under the receiver operating characteristics curve scores indicates that, although both structural density models showed very good performance (with receiver operating characteristics scores greater than 0.7), the 300‐m depth structural density model performed better than the structural density model generated at a depth of 100 m (with their receiver operating characteristics scores being 0.721 and 0.715, respectively). The obtained results corroborate with literature assertion that groundwater occurrence within the Voltaian basin is mainly associated with structural features. It is expected that the outputs of this study would guide future groundwater exploration programmes within the study area.

Coupled processes of groundwater dynamics and land subsidence in the context of active human intervention, a case in Tianjin, China

To address the crisis of water shortage in the North China Plain, the Chinese government implemented the South-to-North Water Transfer Project (SNWTP). In this context, Tianjin, one of the main beneficiaries of this project, has been relieved from water shortages and begun to implement Groundwater Management Plans (GMP) since 2018, which undoubtedly have a significant effect on the groundwater recovery. Meanwhile, this provides a good case for studying the coupled process of ground settlement and groundwater dynamics, especially the soil deformation pattern driven by groundwater level (GWL) rebound. To analyze these issues in detail, field well data was collected to depict groundwater flow field. Moreover, geodetic data was also collated, including leveling, GPS, and InSAR, so that a vertical deformation field with high spatiotemporal resolution could be generated. The results reveal that the GWL of the third confined aquifer which is the main exploitation layer in Tianjin recovered significantly since 2018 with a rate of 2.1 m/yr. The dynamic deformation patterns indicate that the area of land subsidence cones in Tianjin has reduced significantly, accompanied by a sharply declining subsidence rate (decreased from −32.2 mm/yr to −4.5 mm/yr.). Particularly, a significant poroelastic rebound has occurred in the Wuqing and Beichen districts since 2020. Furthermore, due to the delayed pore pressure dissipation in the aquitard, we find a time delay of 0.3–5.5 years between land subsidence and GWL time series, which is far less than that estimated by hydrogeological parameters, as the latter ignored the recharge and recovery capacity of the aquifer system. Finally, an evolution models in Tianjin was presented to illustrate interactive process among the deformation, pore pressure, and hydraulic head. In general, the SNWDP and the GMP has restored the pore pressure of aquifer, reduced the land subsidence, and alleviated the groundwater storage depletion of Tianjin.

Mechanisms influencing changes in water cycle processes in the changing environment of the Songnen Plain, China

The process of the land-surface water cycle has undergone substantial changes as a result of climate change and human activities. Disclosing the evolution of the water cycle and its mechanisms in a changing environment is a challenging and hot issue in hydrological science research, which is essential for regional ecological protection and sustainable development. Based on the MIKE SHE/MIKE 11 model, multi-source data are used to simulate the water cycle change process in the Songnen Plain from 1980 to 2020. The study indicates that groundwater data inverted by GRACE and GLDAS data is relatively accurate, which effectively reflects the process of groundwater storage change in particular regions. Moreover, the surface-groundwater coupling model employs strongly correlated inverse groundwater data to simulate the water cycle change process in the Songnen Plain, yielding highly accurate simulation results. In terms of the impact of climate change and human activities on the water cycle process, climate change is the primary cause of changes in the regional water cycle, with contributions to actual evapotranspiration, surface runoff, and groundwater level of 77.04 %, 70.88 %, and 67.86 %, respectively. Nonetheless, as human activities intensify, their impact on the water cycle process progressively increases. From the perspective of the mechanism of water cycle change, the decrease in wetland area, the expansion of urban areas, and the increase in urban water demand are the primary causes of regional water cycle change between 1995 and 2010. The establishment of water conservation facilities and the dramatic increase in paddy field area are the primary causes of the water cycle change between 2011 and 2020. This study combines multi-source remote sensing data with hydrological models to simulate medium- and large-scale water cycle processes, providing new concepts and methods for examining water cycle processes in water-scarce areas.